Abstract

In the past, several popular methods have been used to repair fractures in various chelonian species. The majority of these have consisted of using various epoxy and resin substances to effectively "glue" the fracture site together.¹ This method was based on the principle of secondary or tertiary intent healing. The fractures were reduced and granulation tissue formed between opposing sides. Reported healing times with this methodology have ranged from one to two years.²

An alternative method for fracture reduction was developed at the North Carolina State University College of Veterinary Medicine and applied on turtles previously hit by a car. This method is a combination of orthopedic fracture fixation techniques. The fractures are repaired with multiple screws connected by orthopedic wire. The screws are placed 1 to 2 centimeters from the fractured edge. The line connecting the screw heads is approximately perpendicular to the fracture line. The screw head is tilted away from the fracture to provide interfragmentary compression. Surgical wire is then placed in a figure-eight fashion around the screws in order to maintain proper fracture reduction. This method allows for primary intention healing and therefore greatly reduces the healing time. In most cases, the screws are removed six months to a year postoperatively.

The primary species on which this technique has been applied are the eastern box turtle (Terrapene carolina carolina) and the yellow bellied slider (Chrysemys scripta scripta). Due to the fact that the box turtle is a land animal and the slider an aquatic one, this technique has been shown to be as effective in water as out. Another consideration when testing the technique on these two species is the fact that they are greatly different in size. The box turtle weighs approximately 400 grams while sliders can weigh up to 2 kilograms. This results in the need for slightly different supplies for the two types of turtles. A 0. 73 mm-diameter (22 Ga.) wire and 2.7 mm cortical bone screws were used in both species. Because of differences in shell thickness, the screw lengths were 6 mm and 8 mm, in the box turtles and sliders, respectively. The length of the screw depends greatly on the thickness of the shell at the fracture sight.

The main advantages of this technique are the greater likelihood of primary intention healing versus secondary and the shorter time to return of normal shell strength. Additionally, the technique has possibilities of being used on other chelonian species including endangered sea turtles.

References

1.  Ed. Kirk. 1989. Current Veterinary Therapy. W.B. Saunders Company, Philadelphia, Pennsylvania, Pp. 789-791.

2.  Mader, Douglas T. 1996. Reptile Medicine and Surgery. W.B. Saunders Company, Philadelphia, Pennsylvania, Pp. 413-417.